This is an extract from Our Human Story, our newsletter about the revolution in archaeology.听Sign up to receive it in your inbox every month.
This month, Our Human Story turns 50 (months old). For the 50th instalment, I thought I would do something a little different: take stock of what鈥檚 happened, and look ahead. I emailed 10 researchers, asking them two questions:
- What has been the biggest advance in human evolution of the past five years? This could be a specific fossil or archaeological site, or something more conceptual like a paradigm shift of some kind 鈥� whatever stands out to you.
- What are you hoping will happen during the remainder of the 2020s? Again, could be a site you鈥檇 like to see excavated or re-analysed, could be a new analytical technique, could be more of a vibe shift 鈥� entirely up to you.
Seven of the researchers sent me answers ahead of my deadline, plus one other contribution came in via Alison George, a features editor at 快猫短视频. I compiled everything and looked for patterns, whether shared themes or stark disagreements. There was a lot of variety: I don鈥檛 think any two people highlighted the same study. However, there were a lot of commonalities, mostly subtler trends in the research that couldn鈥檛 be encapsulated by a single study.
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To present this, I鈥檝e organised it into something roughly chronological, moving from the earliest phases of human evolution to the recent past. We鈥檒l mostly be making sense of the past five years, then finish with a sample of the wishcasting.
If in late 2028 I manage to write a 100th Our Human Story, I鈥檒l check back and see how much of this still holds. I have only one prediction: something in here will turn out to be incorrect, and it鈥檚 even possible it won鈥檛 be my fault.
The many ways hominins evolved to walk
鈥淭he biggest [change is] our increasing awareness of the locomotor diversity in fossil hominins,鈥� says at the University of Toronto in Canada. Instead of a gradual one-way transition from a chimpanzee-like style of walking to a modern human style, hominins found many ways to walk.
This runs throughout the history of hominins, says Viola. In 2019, I reported on Danuvius guggenmosi: an ape that lived in Europe 11.6 million years ago, before the oldest known hominins, but which shows signs of walking on two legs on tree branches. The oldest actual hominin, Sahelanthropus from 7 million years ago, is the subject of ongoing controversy over how it walked, as Viola notes.
If we move forward to the time of Australopithecus, between 4 million and 2 million years ago, we have more diverse fossils and the range of walking styles becomes more apparent. In 2021, fossil footprints in Tanzania from 3.7 million years ago were found to belong to an unidentified hominin, which did not walk like any known species. And in late November I reported on a tracksite in Kenya, where you can literally see footprints from two hominin species with distinct walking styles crossing the same spot, perhaps within days of each other.
鈥淭here were individuals with markedly different gaits and foot morphologies who coexisted in the landscape,鈥� says Viola.
The origins of our own Homo genus
The evolution of the Homo genus is crucial, because it鈥檚 the genus to which we belong.
鈥淲hat I want to single out as the biggest advance in the last five years is the shift to understanding that the origin of our genus, Homo, was not uniquely connected with stone tools and meat eating,鈥� says at the University of Wisconsin-Madison.
According to Hawks, the 鈥渢extbook picture鈥� was that 鈥渟tone tools, meat eating, taller stature, smaller molars and jawbones, and larger brains were all connected with each other, and all coincident with the origin of Homo鈥�. On this view, the evolution of Homo 鈥渓ooked like a single quantum shift 鈥� a very tidy package鈥�.
However, multiple lines of evidence suggested otherwise, and Hawks says, 鈥淭he work of the last five years has really triggered the advance in understanding.鈥� For example, in 2023 researchers described the oldest known Oldowan stone tools from Nyayanga in Kenya. They are 2.6 million to 3 million years old and were found, not with Homo, but with teeth from Paranthropus: hominins with big teeth and small brains. Likewise, a study published in October found that early hominins called Australopithecus , perhaps making and using stone tools. Hawks also highlights a 2022 study that found after the evolution of Homo erectus.
I will add one other data point. In late November, a study concluded that , with early members of a given species having smaller brains than later members of the same species. This was not a given: there had been claims that brain size jumped dramatically in the first Homo, as per the textbook 鈥減ackage鈥� idea.
This all makes for a more complicated story. But, says Hawks: 鈥淭o me this is all exciting because it puts us in a position to test for cause and effect.鈥� By following how different hominins behaved and evolved, it should be possible to see what caused what. For instance, did meat eating enable the growth of bigger brains, or did bigger brains enable more advanced hunting and thus more meat eating?
Humanising the Neanderthals
Let鈥檚 now consider the past million years. During this time, our own species, Homo sapiens, evolved in Africa (more on that in a moment). But there were many other Homo species, like the hobbits (Homo floresiensis) on Flores in Indonesia.
Researchers highlighted progress in the past five years with regard to two groups: Neanderthals and Denisovans. These were two of our closest evolutionary relatives. The Neanderthals lived in Europe and western Asia, the Denisovans in East Asia.
We have lots of Neanderthal remains, and in the past five years our understanding has been fleshed out still further. For instance, researchers have grown 鈥渕ini Neanderthal brains鈥� to 鈥渦nderstand how they develop鈥�, says at the University of Victoria in Canada. Neanderthal neurons fired at different rates in . Likewise, she says, 鈥�Homo sapiens produce more neurons and more connections between neurons鈥�. This gives us hints 鈥渁bout how Neanderthals interacted and learned from the world around them鈥�. She adds that 鈥渢here are even people figuring out what scents Neanderthals and Denisovans preferred鈥�. A 2023 study found Neanderthals were less odour sensitive than humans. However, Denisovans were more sensitive, especially to sweet and sulphur smells. And speaking of the Denisovans, there have also been significant advances in our understanding of them 鈥� but this started from a very different baseline.
鈥淟earning who the northern Denisovans were, physically, has been a very significant breakthrough,鈥� says at the Natural History Museum in London. The Denisovans were first discovered based on genetic evidence, obtained from 鈥渢he very听fragmentary remains鈥� from Denisova cave in the Altai mountains in Russia. This meant we had virtually no idea what they looked like.
Stringer says his recent collaborative work with Chinese colleagues and ongoing research from other teams support the idea that the fossils from Harbin, Dali, Xiahe, , , Hualongdong and Xujiayao are probably all Denisovans. These fossils have been found scattered across southern Asia and are all rather large for such a late hominin, with big teeth. The implication is that the Denisovans were on the larger side.
If you鈥檙e wondering why Stringer said 鈥渘orthern Denisovans鈥�, it鈥檚 because the Denisovans interbred with Homo sapiens, and today the strongest genetic signal of them is in South-East Asia. There are no known Denisovan fossils from there. As a result, says Stringer, 鈥渨e do not yet know the identity of the southern Denisovans, who may have lived in places like Sumatra, Borneo and Sulawesi鈥�.
The changing image of our own species
Now let鈥檚 talk about changes to our understanding of our own species, Homo sapiens.
The old idea that our species originated from a single place in Africa now looks unlikely, says at the Max Planck Institute of Geoanthropology in Jena, Germany. She highlights a 2023 study of modern genetics, which suggests , linked by occasional interbreeding. That same year, evidence emerged of humans living in Senegal, in West Africa, far from our supposed origins in eastern or southern Africa, . 鈥淭his was thrilling because it provides support for the view that humans evolved in multiple different ecoregions and parts of Africa,鈥� says Scerri.
鈥淔or me, it鈥檚 the rewriting of the human origins story for Homo sapiens, specifically on 鈥榦ut of Africa鈥�,鈥� says at Griffith University in Australia. It used to be thought that H. sapiens came out of Africa in a 鈥渟ingle, rapid coastal migration鈥� about 60,000 years ago, but researchers now recognise multiple migrations beginning at least 200,000 years ago. 鈥淲e also have on-the-ground evidence to indicate that migrations were terrestrial, not coastal,鈥� says Petraglia. That migration at 60,000 years ago is still crucial, because most people living outside Africa are descended from those who came out at that time: the earlier migrations seem to have left few genetic traces in modern populations. But these migrations also matter.
Scerri also highlighted our changed understanding of the out-of-Africa migrations. 鈥淗ominins have been dispersing into Arabia from multiple parts of the world over the last 400,000 years,鈥� she says. 鈥淎s the gateway to Africa, it鈥檚 impossible not to wonder how these processes modulated the evolution of our species, and our sister groups, the Neanderthals and Denisovans.鈥�
鈥淔or me perhaps the biggest advance of recent years has been a conceptual shift in our perspective away from the idea that early Homo sapiens were somehow on a trajectory of predestined success, leaving behind all the 鈥榚volutionary losers鈥�,鈥� says at the University of Cambridge. 鈥淚nstead, what we鈥檙e seeing more and more is nuance in the story of early H. sapiens populations: from our complex African emergence, our numerous dispersals into Eurasia and interactions there, and the fact that it seems at least some of the pioneer sapiens populations themselves vanished.鈥�
Finally, researchers have begun paying more attention to a group of humans they previously all but ignored: children. As with so much of human evolution, 鈥渋t is all about relationships鈥�, says Nowell. 鈥淣ot studying children to any serious degree meant that we were ignoring the contributions and experiences of two-thirds of the human population for more than 99 per cent of our time on Earth.鈥� Furthermore, 鈥渂y ignoring their experiences, we were also not accounting for the experiences of others in their communities in relation to them鈥�. This is such an important point that I wrote a feature about it back in March, heavily featuring Nowell and her work.
Wishcasting
As you may have gathered, it鈥檚 been a busy five years. Let鈥檚 end with some predictions and hopes for the next five.
Both Viola and Nowell mentioned the enormous potential of preserved protein in hominin remains. 鈥淧alaeoproteomics,鈥� says Nowell, 鈥渋s revolutionising what we know about the past, and more specifically about past relationships: the kinds of things we actually want to know about Palaeolithic peoples. Advances in this science actually humanise Palaeolithic people in a way that stone tools can鈥檛. We can now picture a Neanderthal father and daughter, or a teenager with a Neanderthal mom and Denisovan dad.鈥�
As well as revealing details of a hominin鈥檚 biology, palaeoproteomics can tell us about species relationships 鈥� and proteins preserve better than DNA. 鈥淎s work on Gigantopithecus has showed, it is possible to analyse peptides from enamel, even in tropical areas, through most of the time interesting for human evolution,鈥� says Viola. He says this should allow us, for example, to verify whether is really a Denisovan, or maybe see where H. floresiensis or Homo luzonensis really fits in the hominin family tree.
Viola also mentioned a completely different possibility: 鈥淎 probably na茂ve hope is that some areas that have become more difficult to work in due to geopolitics will become a bit more accessible again. For me personally, that would be Russia and Central Asia, but parts of Central Africa would also be important.鈥� This is part of a wider push to expand the areas where researchers look for hominin remains. 鈥淭here鈥檚 huge parts of Africa where there is potential to find some evidence for early hominins, and especially for the origins of modern humans.鈥�
In contrast, Stringer has a specific, localised thing he鈥檚 looking forward to. 鈥淚鈥檓 hoping that Wogan Cavern in Pembroke will produce fossils of the last known Neanderthals and the earliest known Homo sapiens found so far in Britain, as well as ancient DNA evidence from their occupations of the site.听Archaeologist Rob Dinnis has been leading the first systematic excavations in this huge, dome-shaped cave, which lies under Pembroke Castle. These have already produced rich evidence of stone tools and animal fossils dating from the period 45,000-11,000 years ago, and there are even fossil hippo bones that show the site must have a sequence of deposits going back even further, to at least 120,000 years ago. I would say that Wogan is the most significant British site for evidence of Neanderthals and early H. sapiens to be uncovered in my lifetime.鈥�
While we鈥檙e talking about Neanderthals, Nowell asks a question that I鈥檝e also wondered about. 鈥淚 am really interested in knowing if Neanderthals and Homo sapiens (and/or Denisovans) ever lived together,鈥� she says. 鈥淲e have evidence of interbreeding, but did that extend to cultural exchanges as well? Was it OK to have a 鈥榦ne-night stand鈥� with that Neanderthal (or that skinny Homo sapiens) but not OK to bring them home?鈥� For anyone who thinks this is prurient, Nowell adds: 鈥淚 am really curious about the full nature of the relationships. Clearly children of mixed parentage such as [the Neanderthal-Denisovan hybrid girl] Denny were cared for and were able to communicate [and] interact with others in their community (or they would not have survived). How far did this tolerance for the other extend? Were they seen as 鈥榦ther鈥�?鈥�
On that note, in early November, researchers including at the University of Bordeaux in France published a new analysis of the period when Homo sapiens arrived in Eurasia and met the Neanderthals. They argue that the evidence best supports . We already knew that humans and Neanderthals interbred, so they suggest that instead of the Neanderthals being outcompeted, the two groups merged into each other. As d鈥橢rrico told my colleague Alison George: 鈥淎ll the early modern humans in Europe have very close Neanderthal ancestors.鈥�
Finally, here鈥檚 Wragg Sykes with a wishcast that struck me as off-the-wall when I first read it but upon reflection seems remarkably plausible. 鈥淎s always, and especially following the astonishing newest permafrost find of , I am hopeful for a frozen Neanderthal to emerge from somewhere in Siberia,鈥� she says. 鈥淚ndeed, any ancient hominin or even partial remains together with their everyday gear would be incredibly informative (while probably raising yet more questions).鈥�
I feel a bit presumptuous adding to all this, but I鈥檒l end with one wish of my own: more fossils from the earliest period of human evolution, between 7 million and 4 million years ago. Compared with later stages, we have almost nothing: four species, each represented by a handful of incomplete specimens, all separated by hundreds of thousands of years. With so little, every new discovery is a major one.
